Flash-powder.



UNITED STATES PATE T; OFFICE. I

nnsusrnwniss on s'rnnsnuae, ennuiiiirl' FLASH-POWDER.

SPECIFICATION forming part of Letters IPatent No. 669,331, dated October 9, 1900.

Application filed August 1, 1898. Serial No. 687,4;35- (No specimens.) I

To all whom it mag concern.-

Be it known that 1, AUGUST WEISS, a subject of the German Emperor, residing at Strasdrawbacks aluminium tages.

burg, Alsace, Germany, have invented certain new and useful Improvements in Flash- Powder for the Taking of Photographs by Artificial Light, of which'the following is a specification.

The object of thepresent invention is a' fiash-powderfor the taking of photographs by artificial light, which does not firewhen rubbed or struck, but ignites only at a high temperature,fulmin ates in stantaneously,and

tographic light of considerable actinic power.

The flash-powders'hitherto used for photographic purposes are mixtures of magnesium or aluminium. Magnesium powders when ignited produce rays which are neither so bright nor of such actinic power as mixtures of aluminium, so that the latter are preferable as regards the action of thelight. Nevertheless, it has not been possible hitherto to produce mixtures of aluminium which also fully efiect their object as to rapidity of combustion.

Moreover, all hitherto-known aluminium pow-' ders are extremely dangerous to handle, be-' ing caused to ignite by the least friction or the slightest concussion and throwing out during the combustion igniferous sparks in all directions. In consequence of these important V powders in spite of their greatactinic power have not been adopted, and their practical applicability in connec t1on with photography has been definitively denied by authorities on the subject- The mixture of aluminium which forms the obect of the present invention proves the contrary and does not present these disadvantioned, as it will not ignite even if struck sharply with a hammer, but only at a high temperature-for instance, by means of the explosive substance of alucifer match sub- 'jeoted to friction-but then ignites surely and quickly and fulminates instantaneously.

- By means of the present invention accordingly the great actinic power of the aluminium light becomes applicable to the fullest extent 'ofthe present invention.

chlorate of potassium,

It is free from the drawbacks men-- most favorable circumstances in opposition to the adverse opinions of photographic experts, and herein lies the new technical effect This efiect is produced by the hitherto-unknown mixture of powdered aluminium and powdered perchlo- The mixture is-made in while the proportions oi. the constituents of the mixture differ considerably. andjare to be measured rate of potassium.

that is to say, the whetheramederately quick, quick combustiorris proportions depend upon production of smoke more or less prevented; Experiments made with this ob ect have for photographic purposes and under the- 6o ing to the purpose in each' particular casequick; or very: to be efiected and the shown that mixtures of eighty-five1partsof j perchlorate of potassium with fifteen parts of aluminium as well as forty parts of the former with sixty parts of alu inium, give useful relimits from eighty-five to forty parts of perwith corresponding suits, so that all mixtu es lying between these parts (from fifteen. to sixty) of aluminium, r'er spectively, may be regarded generally as suitable for photographic purposes.

'A suitable mixture which gives average et- I fects in relation both to quickness of combustion and quantity of smoke resulting is one, for instance, composed of sixty parts of perchlorate of potassium minium.

Having now particularly described the 'nature of this invention,

I declare that what I claim is As a new article of manufacture, a flashtaking photographs by an n powder for use in tificial light, consisting of a mixture of powdered aluminium and powdered perchlorate of potassium, in proportions substantially as set forth.

vIn testimony whereof I have hereunto set' my hand in presence of two subscribing witnesses. I AUGUST WEISS.

Witnesses: I v

H, D. JAMESON,

A. NUTTING.

to forty parts of aln; 

